Chemically synthesized DNAs and RNAs (hereinafter, referred to as synthesized nucleic acids) have received attention as probes for genetic analysis as well as pharmaceutical drugs. Use of the synthesized nucleic acids for these purposes requires binding these synthesized nucleic acids to, for example, solids (e.g., glass, plastics, or polymers) or functional molecules (e.g., fluorescent materials, polyethylene glycol, or peptides). Covalent bonds via amino groups introduced in the synthesized nucleic acids are widely used in the formation of this binding.
An amino group is introduced to the 5′ or 3′ end of each synthesized nucleic acid at the preparation stage of the synthesized nucleic acid so as not to inhibit its interaction with a nucleic acid complementary thereto and/or a nucleic acid-binding protein. The synthesized nucleic acid is typically prepared by nucleic acid strand extension in a direction from the 3′ end toward the 5′ end. The introduction of an amino group to the 5′ end is therefore carried out by the binding of an amino group-containing amidite reagent thereto at the final stage of nucleic acid synthesis. On the other hand, the introduction of an amino group to the 3′ end is carried out by the sequential synthesis of nucleic acids on a solid-phase carrier bound in advance with amino groups.
Heretofore, a compound containing an amino group bound to the end of a linear hydrocarbon group has been widely used in the amino group introduction to the 3′ end (Non Patent Literatures 1 and 2). The amino group introduced using such a compound, however, is low reactive due to the simple structure in which the amino group is bound to the linear hydrocarbon group. Thus, use of this amino group produces insufficient efficiency of binding between the synthesized nucleic acid and a functional molecule or immobilization of the synthesized nucleic acid onto a solid. For this reason, an excessive amount of the reagent must be used to compensate for the low reactivity, resulting in an undesired rise in chemical modification cost for the synthesized nucleic acid.
In order to solve these problems, the present inventors have developed a technique of introducing highly reactive amino groups to synthesized nucleic acids and consequently successfully developed an oligonucleotide probe having an amino group and a carbamate structure (Patent Literature 1).

As shown in the above general formula, this oligonucleotide probe has an amino linker moiety consisting of an amino group-alkyl group (linking group)-oxycarbonylamino structure (hereinafter, referred to as an aminoalkyloxycarbonylamino structure). By virtue of this feature, the amino group of the oligonucleotide probe described in Patent Literature 1 can be bound with a molecule of interest with high binding efficiency and/or immobilization efficiency, compared with amino groups introduced in synthesized nucleic acids by the conventional techniques (Patent Literature 1 and Non Patent Literature 3).